This spacecraft was a one-off high-apogee Earth satellite developed to acquire data on trajectory-measurement techniques on future lunar orbital missions. By perfecting such techniques, engineers could accurately measure trajectories of future lunar orbiters affected by anomalies in the Moon's gravitational field.

Mission designers had planned to send the probe into a highly elliptical orbit with an apogee of 250,000 kilometers, but the Blok L upper stage evidently cut off too early. Instead, the spacecraft, named Kosmos 159, entered a lower orbit of 260 x 60,710 kilometers at 51.7? inclination.

Despite the incorrect orbit, controllers no doubt used the spacecraft for its original mission. No data is available on when the ground lost contact with the spacecraft. Kosmos 159 re-entered Earth's atmosphere on 11 November 1967.

Key Dates

16 May 1967: Launch

11 Nov 1967: Re-Entered Earth's Atmosphere

Status: Partial Success

Fast Facts

Although this mission wasn't sent to the Moon, it was intended to pave the way for more ambitious lunar missions.